Hitherto, in the medical field, there is widely used a method whereby aggregation patterns of blood corpuscle particles, latex particles, and carbon particles are discriminated and various components (for instance, blood type, various antibodies, various proteins, etc.) in the blood, virus, and the like are detected and analyzed. A microtiter method is relatively widely used as such an aggregation pattern discriminating method.
According to the microtiter method in the immunity measurement, the blood is aggregated on a microplate by a predetermined method and the presence or absence of the aggregation is examined or an area or the like of the aggregation pattern is calculated, thereby measuring a microquantity of immune component. Hitherto, the judgement of the presence or absence of the aggregation has been performed by the eyes. However, in recent years, automatization of such a judgement is also being developed.
The discrimination regarding the aggregation patterns is integratedly executed by a method whereby the presence or absence of aggregation is discriminated by detecting a distribution of particles in a translucent well (reaction vessel) and identifying an aggregation of particles as an area of the well whose luminance is equal to or less than a predetermined luminance level, or by comparing the particle distribution with a reference aggregation pattern or a reference non-aggregation pattern, or further by making continuous step-wise dilution series of specimen and samples, or the like.
Automatization of the discrimination of the aggregation patterns is accomplished by: optical means; and electrical arithmetic processing means for electrically arithmetically processing aggregation patterns which are obtained by the optical means.
FIG. 9 shows a conventional example. In the conventional example shown in FIG. 9, an aggregation pattern P of particles in a well (reaction vessel) 100A formed on a microplate 100 is optically projected onto a one-dimensional CCD (charge coupled of vice) sensor) 101. The CCD sensor 101 or the microplate 100 is relatively sequentially finely moved in the direction perpendicular to the paper surface, causing the CCD sensor to occupy a plurality of scanning positions relative to the reaction vessel, thereby enabling the one-dimensional CCD sensor to scan the pattern P many times (see FIG. 11), thus obtaining a (bright and dark) two-dimensional image of the aggregation pattern P. In FIG. 9, reference numeral 102 denotes a light source; 103 an image forming lens; and 104 a lens holder.
In the above conventional example, however, there are the following various problems.
An aggregation image peripheral portion (portion other than the image) becomes dark due to influences by aberrations of the lens holder 104 and the lens 103 and the like and an output of the CCD sensor corresponding to such a peripheral portion becomes remarkably dark at both edge portions E and F of a window width L of such a portion as shown in FIG. 10. Particularly, the data obtained are collected and a solid as shown in FIG. 11 is formed. After that, the aggregation pattern is discriminated by using area data of a cross sectional plane surface which is obtained by cutting the solid at a proper threshold level T. In the case of executing such a discrimination, for instance, as shown in FIG. 12, dark portions Z.sub.1, Z.sub.2, and Z.sub.3 are largely displayed as area data (solid line portions in the diagram) due to influences by the dark portions of the aggregation image peripheral portion, disturbance lights, and electrical noises.
FIG. 13(a) shows an output waveform in the case where the microplate is not inserted. FIG. 13(b) shows an output waveform in the case where the microplate has been inserted. FIG. 13(c) shows an output waveform in the case where the bottom surface of the reaction vessel of the plate is cloudy due to influences by a material and a surface process. As will be obviously understood from the above diagrams, there is a case where the brightness and darkness of the light due to the shape and material of the microplate, the reaction vessel, surface process, and the like are mixed as noises into the output signal and exert an influence on the area data.
As shown in FIG. 13(d), there is also a case where the brightness and darkness of the light due to the uneven illumination exert an influence on the area data.
As shown in FIGS. 14(a) to 14(d), in the case of a doughnut-like image such that the aggregation image is large and the central portion is bright, the area data largely differs in dependence on the setting of the threshold level as will be obviously understood from FIG. 14(d), so that it is very difficult to accurately discriminate the aggregation pattern using area data.
It is an object of the invention to avoid the inconveniences of such a conventional example and, more particularly, to provide a particle aggregation pattern discriminating method which can fairly improve discriminating accuracy as compared with the conventional method.
The invention uses a method of discriminating a particle aggregation pattern whereby a plate for use in aggregation reaction examination and having one or two or more reaction vessels is provided, a bottom surface of each of the reaction vessels is uniformly illuminated through the plate for the aggregation reaction examination by light emitting means arranged on one side of the plate, transmitted light is received through image forming lenses by a one-dimensional photosensitive device arranged on the other side of the plate for the aggregation reaction examination, and a particle distribution is formed on the bottom surface of the reaction vessel as a result of particles precipitated from the reaction solution stored in the reaction vessel. The transmitted light provides an image of the particle distribution, which image is fetched by the photosensitive device as light reception data. An output signal of the one-dimensional photosensitive device is processed to thereby form at least one transmission luminous intensity curve, and an aggregation pattern is discriminated on the basis of the transmission luminous intensity curve in accordance with a predetermined reference, wherein transmission luminous intensity curve data representing an empty state of the reaction vessel is previously stored into a memory, the reaction solution is stored into the reaction vessel, transmission luminous intensity curve data representing a state in which the particles have precipitated after the elapse of a predetermined time is subsequently fetched, waveform data of only an aggregation image is calculated by executing predetermined arithmetic operations on the basis of the transmission luminous intensity curve data representing precipitated particles and the transmission luminous intensity curve data representing the empty vessel, and an aggregation pattern is discriminated on the basis of the calculated waveform data of only the aggregation image.